export type SignalMessage =
| { type: 'join';  roomId?: string } 
| { type: 'other_joined';  roomId: string; joinerId: string, to:string }
| { type: 'leave';  roomId: string }
| { type: 'left',  roomId: string}
| { type: 'bye';  roomId: string }
| { type: 'joined';  roomId: string, clientId: string }
| { type: 'list' ; roomId: string }
| { type: 'offer'; from: string; to: string; payload: any ; roomId: string } 
| { type: 'answer'; from: string; to: string; payload: any ; roomId: string }
| { type: 'candidate'; from: string; payload: any ; roomId: string }
| { type: 'error'; message: string ; roomId: string }
| { type: 'full',  roomId: string };